Photocatalytic degradation of fungicide difenoconazole via photo-Fento process usingα-Fe2O3

Abstract

Nowadays, Human consumption leads to massive industrial sector manufacturing. Pesticides are one of the most toxic chemicals widely used to increase agricultural production. Those compounds present several threats to the environment. The photodegradation of difenoconazole (DFL) fungicide was carried out via Photo-Fenton process using synthesized α-Fe2O3 nanoparticles. The α-Fe2O3 was prepared using hydrothermal approach at 180 °C with ferric chloride and sodium hydroxide reagents. The sample was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman analysis. Average crystallite size has been recorded to be 27 nm and the surface area was found to be SBet = 24.82 m2/g. DFL removal has been tested under divers systems: UV photolysis, UV/H2O2, UV/α-Fe2O3, Fenton and Photo-Fenton process. The kinetic has been monitored using High-Performance Liquid Chromatography (HPLC). All irradiation tests were achieved at 254 nm using UVC Lamp. An optimization of reaction conditions (pH, oxidant concentration, and catalyst dosage) were performed As a result, it was demonstrated that Photo-Fenton process (UV/α-Fe2O3/H2O2) as most effective for DFL removal. The optimal catalyst dose of α-Fe2O3 for high removal rate is about 0.5 g/l at initial solution pH. The mineralization efficiency attained 83.67%. The oxidation kinetics of DFL was recorded to accord with the pseudo-first order kinetic model. Finally, a possible mechanism pathway was proposed based on detected intermediates using gas chromatography-mass spectrometry (GC-MS) analysis.